The catalytic converter is a device in an internal combustion engine that controls exhaust emissions. It converts pollutants and toxins in the exhaust gas into less-toxic pollutants.
A bad catalytic converter can cause various issues in your vehicle. So, you might be wondering if a bad catalytic converter can reduce the gas mileage in your car. Let’s find out if a bad catalytic converter causes bad gas mileage.
Can a bad catalytic converter cause bad gas mileage?
A bad catalytic converter usually means that it is clogged and the airflow is reduced. So, due to a bad catalytic converter, the vehicle has to burn extra fuel, resulting in bad gas mileage. Along with increasing the waste gas and gas bill, it worsens the clog itself.
A bad catalytic converter will most definitely cause a bad gas mileage. As a result of a damaged or defective catalytic converter, the car will consume more fuel to accelerate and remain at a constant speed.
So, one of the major reasons for poor gas mileage is a bad catalytic converter.
A catalytic converter basically transforms pollutants and other toxic gasses that are emitted by the engine after combustion into less toxic byproducts.
It usually converts the toxins into carbon dioxide and water vapor, which are far less harmful than the original byproducts such as carbon monoxide, hydrocarbons, and nitrogen oxides.
A catalytic converter becomes and doesn’t function properly when it gets clogged. A clogged catalytic converter will minimize the airflow from your engine.
As a result of the reduced airflow, the exhaust gas will get trapped in your engine, eventually increasing fuel usage.
A catalytic converter can also reduce the airflow if there is a problem in its mechanism.
In that case, the converter won’t be able to transform toxic gasses into less toxic gasses efficiently. It will consume more fuel to convert the byproducts into water vapor and carbon dioxide.
Bad gas mileage is one of the simplest and most noticeable symptoms of a defective catalytic converter to both professional and average drivers. The bad catalytic mileage will also cause overheating and smoking.
Due to the bad catalytic smoke, the car will create black smog which will reduce the fuel efficiency of the engine.
If there is a defect in the catalytic converter, various harmful toxins and pollutants will get emitted into the environment along with the exhaust gas. In that case the car will become harmful to the environment.
To boost the performance, increase the fuel efficiency of the engine, and make the vehicle environment friendly, you must make sure that your catalytic converter is properly functional.
When your vehicle shows a poor gas mileage, you should immediately fix your catalytic converter as it is one of the major symptoms of a bad catalytic converter.
How does a clogged catalytic converter affect gas mileage?
A clogged catalytic converter will hamper the fuel performance of the car. As a result of a clog in the catalytic converter, the vehicle will need more fuel to accelerate and run at a uniform speed, resulting in a bad gas mileage.
A clogged gas mileage reduces the airflow, which traps the exhaust gas in an internal combustion engine. As a result of the trapped exhaust gas in the engine, the engine will burn more fuel to gain speed and run.
Since the exhaust gas will not be able to come out of the engine at its regular speed and time period, it will damage the engine. The engine will get worn out in a very short period of time.
Due to the worn-out engine, it will consume more gas to operate and run the vehicle, resulting in poor fuel performance.
When the catalytic converter is clogged, it won’t be able to convert the pollutants that are created as a result of the ignition in the engine to less toxic gasses.
The vehicle will emit carbon monoxide or nitrogen oxides instead of carbon dioxide and water vapor.
Do catalytic converters reduce or improve gas mileage in a car?
A good and effective catalytic converter improves the gas mileage in a car. A catalytic converter neutralizes and converts harmful compounds in the exhaust gas into fewer pollutant compounds.
It converts compounds like carbon monoxide and nitrogen oxide to carbon dioxide and water vapor.
If the catalytic converter in a car is defective or clogged, the gas mileage in a car will become bad.
Due to the defective catalytic converter, the exhaust gas will remain in the engine for a longer period of time which will increase the fuel consumption of the car.
Will removing catalytic converter improve gas mileage?
The gas mileage will not improve if you remove the catalytic converter from your vehicle. This is due to the fact that the catalytic converter only turns the toxins and pollutants in the exhaust gas into less toxic materials.
Catalytic converters have no effect on gas mileage unless they are malfunctioning, so removing one will have no effect unless it was malfunctioning. So, if you replace a defective or bad catalytic converter, the gas mileage of the car will get better.
This will make sure the exhaust gas flows out of the car in the right manner, improving the overall fuel performance of the vehicle.
What are the symptoms of a bad catalytic converter?
There are numerous symptoms of a bad catalytic converter. It is very important to know the symptoms so that you can fix the catalytic converter as soon as you detect the symptoms. Have a look at the symptoms of a bad catalytic converter:
The car won’t start easily:
One of the major symptoms of a bad catalytic converter is that the car won’t start on the first go. A bad catalytic converter causes the engine to stall due to the increased exhaust which is caused by the trapped exhaust gas in the engine.
Bad fuel efficiency:
When the catalytic converter is clogged, the airflow to the engine will get reduced significantly. When the airflow is reduced in the engine, the engine will receive less oxygen.
The engine will have to work harder if the oxygen level in the engine is lower than usual. As a result, due to a defective catalytic converter, a vehicle will have bad fuel efficiency.
When your vehicle doesn’t gain speed well even after stepping on the gas pedal, it could be another symptom of a bad catalytic converter.
When the catalytic converter is clogged, the engine performance will get reduced. As a result, due to a bad catalytic converter, you will face poor acceleration in your vehicle.
Check engine light is on:
The check engine light turns on when there is some issue in the engine. When a catalytic converter is defective, the exhaust gas will get trapped in the engine, which will turn on the check engine light.
In addition, air-to-fuel ratio sensors can cause the check engine light to illuminate if your vehicle emits high amounts of toxic gasses and pollution.
What causes sudden bad gas mileage in a car?
Understanding what causes a sudden drop in the fuel performance in a car is not as complicated as it may seem to you at first.
There are numerous reasons that can cause sudden bad gas mileage in a car. Let’s take a look at the factors that can cause sudden bad gas mileage in a car.
Bad catalytic converter:
When the catalytic converter is defective, enough air won’t get into the engine. As a result, the oxygen level in the engine will also reduce, which will cause the engine to work harder, resulting in more gas consumption.
So, a bad catalytic converter will cause sudden bad gas mileage.
Improper tire pressure:
The vehicle will have bad gas mileage if the tires are not properly inflated. This is true if the tire pressure is low, high, or different tires have different pressure.
The ideal air pressure for the tires will be displayed on the panel inside your driver’s side door.
Bad air filter:
If the air filter of your vehicle is defective, dirty, or old it won’t be able to provide the engine with the right amount of air it needs to combust the gas. As a result, due to a bad air filter, the fuel efficiency of the car can suddenly drop.
Misfiring or defective spark plugs:
The spark plugs help the engine to ignite the fuel. If the spark plugs are defective or misfiring, the car will need more fuel to run in the proper way. As a result, misfiring spark plugs will definitely reduce the gas mileage.
A bad catalytic converter will reduce the flow of clean air into the engine. There will be less amount of oxygen in the engine due to the shortage of air, causing the engine to work hard and consume more fuel. Thus, a bad catalytic converter will definitely cause bad gas mileage.
I am an automotive enthusiast and have been interested in cars since I was a little kid. I have worked in the automotive industry for many years and have extensive knowledge of vehicles and their engines. I am a father of two and I love spending time with my family.
Read more about the author here.